Portraits in Lichen

The lichens in our yard are doing really well this season with all the extra moisture and dank days. From Wikipedia, "A lichen is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship." According to scientists at Purdue University, yeast may be a third partner that helps defend the colony. Lichens are slow-growing and just need a structure to support them. They make their own food, are not parasites, and do not carry disease.

A saxicolous lichen (grows on rocks),
visible from the kitchen window

Oakmoss lichen (Evernia prunastri),
found in the side yard

I've made an attempt to identify a few species in our yard, using Lichens of the SF Bay Area by iNaturalist. Some forms are very distinctive, and easy to identify. Others are very complex and difficult to distinguish for the beginner. They are colonies, afterall, so may grow in various combinations.

Green rock shield ? (Xanthoparmelia spp.)

Common greenshield lichen (Flavoparmelia caperata)

I found a few descriptive phrases that are handy to know while getting started. Saxicolous lichen grows on rocks; corticolous lichen grows on bark; lignicolous lichen grows on wood that is stripped of bark; and terricolous lichen grows on soil or the ground. Freshwater and marine lichens can occur submerged or in varying water levels. Foliose lichens produce leaf-like flattened, lobed thallus; fruticose lichens grow erect with visible fruiting bodies; and crustose lichens form a crust over their host. With those terms you can at least start describing what you see!

A saxicolous lichen (grows on rocks)

A lignicolous lichen (grows on wood stripped of bark)

I plan to protect these beautiful specimens as much as I can during our landscaping project. They add a lot of character to the yard, and are interesting to observe over time. I also have plans to use some specimens in future dye projects, to see if they yield any interesting colors. Hope you've enjoyed these portraits in lichen.